Tobacco use, in particular cigarette smoking, is the leading preventable cause of death in the United States.1 In addition to lung cancer and respiratory illness, tobacco use is responsible for increased risk of cardiovascular disease (CVD), and is a primary causal factor for two specific types of CVD: coronary heart disease (CHD) and stroke.1,2 More than eighty-one million persons in the United States have at least one form of CVD, and CHD and stroke rank as the first and third leading causes of death, respectively.3,4 Recent research indicates lesbian, gay, bisexual and transgender (LGBT) individuals have the highest rates of tobacco use.9,10 Within this group, sexual minority men (i.e., men who identify as gay, bisexual, or who engage in same sex sexual behavior) have one of the largest smoking disparities, with a smoking rate of more than twice that of their heterosexual counterparts.9 Yet, we know almost nothing about tobacco use in sexual minority men or the extent to which tobacco use may be responsible for increased CVD in this population. Accordingly, the proposed study will utilize both nationally representative and clinic-based data to examine the relationship between the prevalence and patterns of tobacco use among sexual minority men and potential disparities in CVD. In addition the proposed project will also investigate the role of HIV infection as a potential effect measure modifier in the relationship between tobacco use and CVD. These objectives are consistent with the goals of the National Institute on Drug Abuse (NIDA) and relate to NIDA's strategic plan to foster research on health conditions that may inform, influence or interact with drug abuse and addiction, to decrease health disparities related to drug addiction and its consequences, and to decrease the health disparities associated with HIV/AIDS. With access to the resources of Saint Louis University and the Fenway Center for Population Research in LGBT Health, a well-crafted and carefully designed research training plan, and the support of an excellent mentoring team, the applicant is ideally suited to carry out the proposed research. The multi- disciplinary mentoring team brings expertise in the areas of epidemiologic outcomes research, psychiatric epidemiology, LGBT population research, cardiology, and biostatistics, and is fully committed to supporting the applicant throughout the training period. The long term goal of the applicant is to obtain a faculty position and develop an independent research career in the areas of chronic disease epidemiology and LGBT population health, and as such, the proposed research will play a key role in developing the applicant's potential for a promising research career.